349 research outputs found
Commodity risk assessment of Prunus cerasus × Prunus canescens hybrid plants from Ukraine
The European Commission requested the EFSA Panel on Plant Health to prepare and deliver risk assessments for commodities listed in Commission Implementing Regulation (EU) 2018/2019 as 'High-risk plants, plant products and other objects'. This Scientific Opinion covers plant health risks posed by plants of hybrids of Prunus cerasus x Prunus canescens imported from Ukraine, taking into account the available scientific information, including the technical information provided by Ukraine. All pests that may be associated with the hybrids of P. cerasus x P. canescens were evaluated against specific criteria for their relevance for this opinion. None of the pests fulfilled all relevant criteria due to the production method and risk mitigation measures carried out by the nursery; therefore, none were selected for further evaluation
Development and validation of a scoring system to predict response to obeticholic acid in primary biliary cholangitis
Background & aims: Obeticholic acid (OCA) is the only licensed second-line therapy for primary biliary cholangitis (PBC). With novel therapeutics in advanced development, clinical tools are needed to tailor the treatment algorithm. We aimed to derive and externally validate the OCA response score (ORS) for predicting the response probability of individuals with PBC to OCA. Methods: We used data from the Italian RECAPITULATE (N = 441) and the IBER-PBC (N = 244) OCA real-world prospective cohorts to derive/validate a score including widely available variables obtained either pre-treatment (ORS) or also after 6 months of treatment (ORS+). Multivariable Cox regressions with backward selection were applied to obtain parsimonious predictive models. The predicted outcomes were biochemical response according to POISE (alkaline phosphatase [ALP]/upper limit of normal [ULN]<1.67 with a reduction of at least 15%, and normal bilirubin), or ALP/ULN<1.67, or Normal range criteria (NR: normal ALP, alanine aminotransferase [ALT], and bilirubin) up to 24 months. Results: Depending on the response criteria, ORS included age, pruritus, cirrhosis, ALP/ULN, ALT/ULN, GGT/ULN, and bilirubin. ORS+ also included ALP/ULN and bilirubin after 6 months of OCA therapy. Internally validated c-statistics for ORS were 0.75, 0.78, and 0.72 for POISE, ALP/ULN<1.67, and NR response, which raised to 0.83, 0.88, and 0.81 with ORS+, respectively. The respective performances in validation were 0.70, 0.72, and 0.71 for ORS and 0.80, 0.84, and 0.78 for ORS+. Results were consistent across groups with mild/severe disease. Conclusions: We developed and externally validated a scoring system capable to predict OCA response according to different criteria. This tool will enhance a stratified second-line therapy model to streamline standard care and trial delivery in PBC
ReSurveyEurope: A database of resurveyed vegetation plots in Europe
Aims: We introduce ReSurveyEurope - a new data source of resurveyed vegetation plots in Europe, compiled by a collaborative network of vegetation scientists. We describe the scope of this initiative, provide an overview of currently available data, governance, data contribution rules, and accessibility. In addition, we outline further steps, including potential research questions. Results: ReSurveyEurope includes resurveyed vegetation plots from all habitats. Version 1.0 of ReSurveyEurope contains 283,135 observations (i.e., individual surveys of each plot) from 79,190 plots sampled in 449 independent resurvey projects. Of these, 62,139 (78%) are permanent plots, that is, marked in situ, or located with GPS, which allow for high spatial accuracy in resurvey. The remaining 17,051 (22%) plots are from studies in which plots from the initial survey could not be exactly relocated. Four data sets, which together account for 28,470 (36%) plots, provide only presence/absence information on plant species, while the remaining 50,720 (64%) plots contain abundance information (e.g., percentage cover or cover-abundance classes such as variants of the Braun-Blanquet scale). The oldest plots were sampled in 1911 in the Swiss Alps, while most plots were sampled between 1950 and 2020. Conclusions: ReSurveyEurope is a new resource to address a wide range of research questions on fine-scale changes in European vegetation. The initiative is devoted to an inclusive and transparent governance and data usage approach, based on slightly adapted rules of the well-established European Vegetation Archive (EVA). ReSurvey:Europe data are ready for use, and proposals for analyses of the data set can be submitted at any time to the coordinators. Still, further data contributions are highly welcome
Drone-based calibration of AugerPrime radio antennas at the Pierre Auger Observatory
Radio emissions of extensive air showers can be observed at the Pierre Auger Observatory with the AugerPrime Radio Detector (RD). As part of the AugerPrime upgrade, RD is being installed on 1660 water-Cherenkov detectors on an area of about 3000 km2 and consists of dual-polarized Short Aperiodic Loaded Loop Antennas (SALLA). To achieve high measurement precision, RD needs to be well-calibrated, which requires the antenna response pattern to be well-known. We introduce a method to measure the directional response of the SALLA using a well-defined biconical antenna mounted to a drone. The drone-based setup possesses active stabilization and precise pointing with the use of a gimbal. Additionally, the drone’s position is tracked using differential GPS with O(cm) precision. This setup allows us to precisely extract the antenna response pattern from any direction in the frequency range of 30 − 80 MHz. In a recent in-situ campaign, calibration measurements of the AugerPrime radio detector have been performed. First results of these measurements are presented and compared to simulations
Scaler Rates from the Pierre Auger Observatory: A New Proxy of Solar Activity
The modulation of low-energy galactic cosmic rays reflects interplanetary magnetic field variations and can provide useful information on solar activity. An array of ground-surface detectors can reveal the secondary particles, which originate from the interaction of cosmic rays with the atmosphere. In this work, we present an investigation of the low-threshold rate (scaler) time series recorded in 16 yr of operation by the Pierre Auger Observatory surface detectors in Malargüe, Argentina. Through an advanced spectral analysis, we detected highly statistically significant variations in the time series with periods ranging from the decadal to the daily scale. We investigate their origin, revealing a direct connection with solar variability. Thanks to their intrinsic very low noise level, the Auger scalers allow a thorough and detailed investigation of the galactic cosmic-ray flux variations in the heliosphere at different timescales and can, therefore, be considered a new proxy of solar variability
Improving the photon sensitivity of the Pierre Auger Observatory with the AugerPrime Radio Detector
The AugerPrime upgrade represents a significant enhancement in the capability of the Pierre Auger Observatory to detect air showers. Central to this advancement is the installation of a radio antenna atop each existing Surface Detector station, constituting the Radio Detector (RD). The RD enhances the sensitivity of the Surface Detector to the electromagnetic component of air showers. Hence, the new detector presents an opportunity for the discovery of rare particles such as ultra-high-energy photons. This contribution shows the development efforts towards an RD trigger with focus on the detection of rare particles. The radio trigger designed for the detection of photon-induced events will be outlined, and the challenge of a radio background consisting of human-made noise is discussed. The trigger efficiency and reconstruction accuracy are studied with simulations. The presentation will conclude by summarizing the effectiveness of the new detector component
Towards a Cosmic-Ray Energy Scale with the Auger Engineering Radio Array
Radio detection of cosmic-ray (CR) induced extensive air showers with digital antenna arrays is a matured technique by now. At the Pierre Auger Observatory, the Auger Engineering Radio Array (AERA) has been measuring air-shower signals in conjunction with the particle detectors of the surface detector (SD) for over ten years. For an absolute determination of the CR energy with the Auger baseline detectors, the shower size estimator from the SD is calibrated with the energy scale of the fluorescence detector (FD). However, AERA has an independent access to the energy scale through the reconstructed radio signals. The hybrid detectors at the Pierre Auger Observatory offer the unique opportunity to compare the two independent energy scales. In this contribution, we present our envisaged methodology for cross-checking the agreement between the energy scales of the FD and AERA using hybrid SD-AERA shower data and simulations. We show individual steps of our radio signal reconstruction and highlight the key ingredients for calibrated energy measurements
Search for a diffuse flux of photons with energies above tens of PeV at the Pierre Auger Observatory
Diffuse photons of energy above 0.1 PeV, produced through the interactions between cosmic rays and either interstellar matter or background radiation fields, are powerful tracers of the distribution of cosmic rays in the Galaxy. Furthermore, the measurement of a diffuse photon flux would be an important probe to test models of super-heavy dark matter decaying into gamma-rays. In this work, we search for a diffuse photon flux in the energy range between 50 PeV and 200 PeV using data from the Pierre Auger Observatory. For the first time, we combine the air-shower measurements from a 2 km2 surface array consisting of 19 water-Cherenkov surface detectors, spaced at 433 m, with the muon measurements from an array of buried scintillators placed in the same area. Using 15 months of data, collected while the array was still under construction, we derive upper limits to the integral photon flux ranging from 13.3 to 13.8 km−2 sr−1 yr−1 above tens of PeV. We extend the Pierre Auger Observatory photon search program towards lower energies, covering more than three decades of cosmic-ray energy. This work lays the foundation for future diffuse photon searches: with the data from the next 10 years of operation of the Observatory, this limit is expected to improve by a factor of ∼ 20
Measuring the muon content of inclined air showers using AERA and the water-Cherenkov detector of the Pierre Auger Observatory
We present a novel approach for assessing the muon content of inclined air showers based on a combined analysis of the radio emission and particle footprint. We will use the radiation energy reconstructed by the Auger Engineering Radio Array (AERA) as an energy estimator and estimate the muon number independently with the water-Cherenkov detector array (WCD) of the Pierre Auger Observatory. We focus our analysis on air showers with primary energy above 4 EeV to ensure full efficiency of the WCD with a grid spacing of 1500 m. Over approximately six years of data, we identify a set of 31 high-quality events that are used in the analysis. The estimated muon content in data is compatible with the one for an iron primary as predicted by current-generation hadronic interaction models. This result can be interpreted as a deficit of muons in simulations as a lighter mass composition is expected from Xmax measurements. Such a muon deficit was already observed in previous analyses of the Auger Collaboration and is now confirmed for the first time with radio data
- …
